/* $Id: Rule.java 467222 2006-10-24 03:17:11Z markt $
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.tomcat.util.digester;

import org.xml.sax.Attributes;

/**
 * Concrete implementations of this class implement actions to be taken when a
 * corresponding nested pattern of XML elements has been matched.
 */

public abstract class Rule {

	// ----------------------------------------------------------- Constructors

	/**
	 * Constructor sets the associated Digester.
	 * 
	 * @param digester
	 *            The digester with which this rule is associated
	 * @deprecated The digester instance is now set in the
	 *             {@link Digester#addRule} method. Use {@link #Rule()} instead.
	 */
	public Rule(Digester digester) {

		super();
		setDigester(digester);

	}

	/**
	 * <p>
	 * Base constructor. Now the digester will be set when the rule is added.
	 * </p>
	 */
	public Rule() {
	}

	// ----------------------------------------------------- Instance Variables

	/**
	 * The Digester with which this Rule is associated.
	 */
	protected Digester digester = null;

	/**
	 * The namespace URI for which this Rule is relevant, if any.
	 */
	protected String namespaceURI = null;

	// ------------------------------------------------------------- Properties

	/**
	 * Return the Digester with which this Rule is associated.
	 */
	public Digester getDigester() {

		return (this.digester);

	}

	/**
	 * Set the <code>Digester</code> with which this <code>Rule</code> is
	 * associated.
	 */
	public void setDigester(Digester digester) {

		this.digester = digester;

	}

	/**
	 * Return the namespace URI for which this Rule is relevant, if any.
	 */
	public String getNamespaceURI() {

		return (this.namespaceURI);

	}

	/**
	 * Set the namespace URI for which this Rule is relevant, if any.
	 * 
	 * @param namespaceURI
	 *            Namespace URI for which this Rule is relevant, or
	 *            <code>null</code> to match independent of namespace.
	 */
	public void setNamespaceURI(String namespaceURI) {

		this.namespaceURI = namespaceURI;

	}

	// --------------------------------------------------------- Public Methods

	/**
	 * This method is called when the beginning of a matching XML element is
	 * encountered.
	 * 
	 * @param attributes
	 *            The attribute list of this element
	 * @deprecated Use the {@link #begin(String,String,Attributes) begin} method
	 *             with <code>namespace</code> and <code>name</code> parameters
	 *             instead.
	 */
	public void begin(Attributes attributes) throws Exception {

		; // The default implementation does nothing

	}

	/**
	 * This method is called when the beginning of a matching XML element is
	 * encountered. The default implementation delegates to the deprecated
	 * method {@link #begin(Attributes) begin} without the
	 * <code>namespace</code> and <code>name</code> parameters, to retain
	 * backwards compatibility.
	 * 
	 * @param namespace
	 *            the namespace URI of the matching element, or an empty string
	 *            if the parser is not namespace aware or the element has no
	 *            namespace
	 * @param name
	 *            the local name if the parser is namespace aware, or just the
	 *            element name otherwise
	 * @param attributes
	 *            The attribute list of this element
	 * @since Digester 1.4
	 */
	public void begin(String namespace, String name, Attributes attributes)
			throws Exception {

		begin(attributes);

	}

	/**
	 * This method is called when the body of a matching XML element is
	 * encountered. If the element has no body, this method is not called at
	 * all.
	 * 
	 * @param text
	 *            The text of the body of this element
	 * @deprecated Use the {@link #body(String,String,String) body} method with
	 *             <code>namespace</code> and <code>name</code> parameters
	 *             instead.
	 */
	public void body(String text) throws Exception {

		; // The default implementation does nothing

	}

	/**
	 * This method is called when the body of a matching XML element is
	 * encountered. If the element has no body, this method is not called at
	 * all. The default implementation delegates to the deprecated method
	 * {@link #body(String) body} without the <code>namespace</code> and
	 * <code>name</code> parameters, to retain backwards compatibility.
	 * 
	 * @param namespace
	 *            the namespace URI of the matching element, or an empty string
	 *            if the parser is not namespace aware or the element has no
	 *            namespace
	 * @param name
	 *            the local name if the parser is namespace aware, or just the
	 *            element name otherwise
	 * @param text
	 *            The text of the body of this element
	 * @since Digester 1.4
	 */
	public void body(String namespace, String name, String text)
			throws Exception {

		body(text);

	}

	/**
	 * This method is called when the end of a matching XML element is
	 * encountered.
	 * 
	 * @deprecated Use the {@link #end(String,String) end} method with
	 *             <code>namespace</code> and <code>name</code> parameters
	 *             instead.
	 */
	public void end() throws Exception {

		; // The default implementation does nothing

	}

	/**
	 * This method is called when the end of a matching XML element is
	 * encountered. The default implementation delegates to the deprecated
	 * method {@link #end end} without the <code>namespace</code> and
	 * <code>name</code> parameters, to retain backwards compatibility.
	 * 
	 * @param namespace
	 *            the namespace URI of the matching element, or an empty string
	 *            if the parser is not namespace aware or the element has no
	 *            namespace
	 * @param name
	 *            the local name if the parser is namespace aware, or just the
	 *            element name otherwise
	 * @since Digester 1.4
	 */
	public void end(String namespace, String name) throws Exception {

		end();

	}

	/**
	 * This method is called after all parsing methods have been called, to
	 * allow Rules to remove temporary data.
	 */
	public void finish() throws Exception {

		; // The default implementation does nothing

	}

}
